Concrete bridge.



No. 887,189. PATENTED MAY 12, 1908. M. 0. BURNETT.

CONCRETE BRIDGE.

APPLICATION FILED DEO. 14, 1906. BENEWBD MAB. 21, 1908.

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MILO O. BURNETT, OF DES MOINES, IOWA..

CONCRETE BRIDGE.

Specification of Letters Patent.

Patented May 12, 1908.

Application filed. December 14, 1906, Serial No. 347,898. Renewed March21, 1908. Serial No. 422,538.

To all 'whom it may concern.'

Be it known that l, MILo O. BURNETT, a citizen of the United States,residing at Des Moines, in the county of Polk and State of Iowa, haveinvented a new and useful Concrete Bridge, of which the following is aspecification.

My obj ect is to facilitate the construction of a concrete bridge, savetime, labor and expense in construction and improve its strength andefficiency by reinforcing it with straight metal bars that are flexiblyconnected with each other and lsecurely retained together in position asdesired to pro duce arches of different curvature by concrete andvwithout any extraneous fastening devices.

My invention consists in the construction, arrangement and combinationof, parts as hereinafter set forth, pointed out in my claims andillustrated in the accompanying drawings, in which:

Figure 1 shows the arrangement and combination of a plurality ofstraight metal barselbowshaped at their ends and a plurality of straightbars clamped fast between said elbow-shaped ends as required to producea flexible reinforcement in the arches of bridges that may vary indegrees of curvature. Fig. 2 is a modification of Fig. 1 and shows theelboweshaped ends of the straight bars alternately reversed in positionto conneet them to produce a flexible metal reinforcement in a concretearch. Fig. 3 shows a concrete arch bridge, partly in section, to showthe flexible metal reinforcement embedded in the concrete. Fig. 4 is anenlarged transverse sectional view of the concrete arch in which theelbow ends of the straight metal bars alternately project in reverseways relative to the cross bars that connect them. Fig. 5 is an enlargedtransverse sectional view on the line a'. a; of Fig. 3 and shows all theelbow ends of the straight metal bars projecting upwards as in Fig. 1.Fig. 6 is an enlarged top view of a section of the flexiblereinforcement in which the elbow shaped ends of the metal bars allproject upwards relative to the straight metal bars that connect them.Fig. 7 is a view corresponding with Fig. 6 and the elbow ends of thebars alternately projecting up and down relative to the straight crossbars that connect them as required to produce a flexible reinforcementextending from end to end in a'n arch composed of concrete.

' gled ends of the bars 1 as shown.

The numerals 10 designate straight metal bars that may vary in size,length and weight and that are bent into elbow shape at their ends asshown and adapted to be flexibly connected by means of straight metalbars 12 as shown in Figs. 1, 6 and 7 without any extraneous means ofholding them securely together.

After the abutments of a bridge are made and a scaffold erected betweenthem for pro ducing an arch with concrete material and the base 13 of anarch produced on the scaffold, my flexible metal reinforcement composedof the parts 10 and 12, as shown in Fig. l or F 2, is readily placed onthe arched base, regardless of its degree of curvature, by successivelyplacing the metal bars in proper position relative to each other toconnect them. By then filling concrete on top of them they are embeddedtherein and concealed and immovably fixed to strengthen and uphold thearch and any weight that may pass over the bridge.

' The end portions of the bars .l0 that have elbows at their ends are inoverlapping position and the cross bars l2 must be extended between theelbows or right-angled extensions at the ends of the bars 10 and incontact with said extensions ,to securely clamp them fast as required toconnect them to produce a rigid frame by embedding the metal bars thusconnected in concrete and without the need of rivets,l bolts or anyother fastening devices.

lt is obvious that after the concrete arch is produced upon andsupported by a scafi fold the bars l() can be readily placed, one

at a time, in a row to extend horizontally across the concrete arch andthen a second row of the bars 10 placed in parallel position to theVfirst row and in this way a plurality of rows, as many as may be wantedand the rows as close together as desired. And when rows composed ofbars l() are thus placed upon and su ported by the concrete arch acomplete ske eton metal arch is produced by simply placing bars 12between the right an- Y .No support but the concrete arch is requiredfor the skeleton arch thus reduced and no extraneous fastening devicesare required for securely binding all the bars l() and 12 togethersecurely to prevent lateral or longitudinal motion of any one of thebars or the complete skeleton arch.

Having thus set forth the purpose of my invention and the manner of itsconstruction, the practical operation and utility thereof will beobvious.

What I claim as new and desire to secure by Letters-P atent, is:

l. In a concrete bridge and the like, a

skeleton nietal frame comprising a plurality of rows of straight barshaving their ends bent at right angles to produce elbows and cross barsclamped fast between said elbows without any extraneous fasteningdevice.

2. In a concrete bridge and the like, a plurality of metal barselbow-shaped at their ends and placed in parallel rows and a pluralityof metal cross bars placed between the said elbows and all the barssupported upon a concrete arch, as set forth.

3. In an arch for a bridge and the like, straight metal bars bent atright angles at their ends and placed in parallel lines and the saidparallel lines of bars connected by placing straight cross bars betweencontiguous elbows of the bars in arallel lines and the skeleton inetalframe t us constructed supported upon a concrete arch asset forth.

4. A complete arch in a concrete bridge comprising a concrete arch, askeleton metal frarne and reinforcement consisting of a plurality ofmetal bars elbow-shaped at their ends and a plurality of cross barsfastened between the elbows at the ends of said bars and embedded in theconcrete placed on top of the skeleton rnetal f'rarne and concrete arch,as set forth.

5. A concrete bridge comprising abut- R. H. ORwrG, THOMAS G. Onwre.

